Final answer:
Affinity is the term that describes the strength of the interaction between a substance, like an antibody or drug, and its specific target. It determines how strongly and stably a molecule binds to its intended target, distinguishing it from related terms like efficacy, potency, and selectivity.
Step-by-step explanation:
The term that describes the ability of a substance to bind to a particular target is Affinity. Affinity refers to the strength with which a molecule such as an antibody or a drug binds to a specific target, like an antigen or receptor. An example would be the binding between antibodies and antigens, where a higher affinity indicates a stronger and more stable interaction. This is crucial for the biological function of antibodies, as it determines how effectively they can neutralize or mark pathogens for destruction. While terms such as efficacy, potency, and selectivity are all important pharmacological properties, they refer to different aspects of a substance's action. Efficacy relates to the maximal effect a drug can produce, potency to the amount of drug needed to achieve a given effect, and selectivity to the ability of a drug to affect a particular target without impacting other targets or systems.